Just to balance the above, biking with a guiding company can be more hassle – you never start at the time you want (there’s usually someone hung over with a flat they didnt fix, a trail centre numpty with a badly maintained bike, someone with tubelesss tyres that have issues, or a dodgy press fit BB with no spares etc). Then there’s the waiting around on the ride while more faffing goes on, you wait for the underskilled guy who’s mates told him to MTFU just before he injures himself on a small jump or rock garden, someone looses their lift pass etc. And you might feel obliged to spend the evening doing what others want to do (or eat and drink in the same place every day).
Horses for courses, Northwiind is right though, if you dont know the area then you will probably miss the best trails if you go alone. But, if you are just going to a resort, then it’s easy to camp, get the first lift and ride all day if you do DIY, and definitely cheaper.
We mix and match depending where we are going.